mx.collections.SortField - ActionScript® 3.0 Reference for the Adobe® Flash® Platform

Package	mx.collections
Class	public class SortField
Inheritance	SortField EventDispatcher Object
Implements	ISortField

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

Starting with Flex 4.5, Adobe recommends that you use the spark.collections.SortField class as an alternative to this class.

Provides the sorting information required to establish a sort on a field or property in a collection view. The SortField class is meant to be used with the Sort class. Typically the sort is defined for collections of complex items, that is items in which the sort is performed on properties of those objects. As in the following example:


     var col:ICollectionView = new ArrayCollection();
     col.addItem({first:"Anders", last:"Dickerson"});
     var sort:Sort = new Sort();
     sort.fields = [new SortField("first", true)];
     col.sort = sort;

There are situations in which the collection contains simple items, like String, Date, Boolean, etc. In this case, sorting should be applied to the simple type directly. When constructing a sort for this situation only a single sort field is required and should not have a name specified. For example:


     var col:ICollectionView = new ArrayCollection();
     col.addItem("California");
     col.addItem("Arizona");
     var sort:Sort = new Sort();
     sort.fields = [new SortField(null, true)];
     col.sort = sort;

By default the comparison provided by the SortField class does not provide correct language specific sorting for strings. For this type of sorting please see the spark.collections.Sort and spark.collections.SortField classes.

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The <mx:SortField> tag has the following attributes:

  <mx:SortField
  Properties
  caseInsensitive="false"
  compareFunction="Internal compare function"
  descending="false"
  name="null"
  numeric="null"
  />

Related API Elements

mx.collections.ICollectionView
mx.collections.Sort
spark.collections.Sort
spark.collections.SortField

Public Properties

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	Property		Defined By
		arraySortOnOptions : int [read-only] This helper property is used internally by the findItem() and sort() methods.	SortField
		caseInsensitive : Boolean Specifies whether the sort for this field should be case insensitive.	SortField
		compareFunction : Function The function that compares two items during a sort of items for the associated collection.	SortField
		constructor : Object A reference to the class object or constructor function for a given object instance.	Object
		descending : Boolean Specifies whether this field should be sorted in descending order.	SortField
		name : String The name of the field to be sorted.	SortField
		numeric : Object Specifies that if the field being sorted contains numeric (number/int/uint) values, or string representations of numeric values, the comparator use a numeric comparison.	SortField
		prototype : Object [static] A reference to the prototype object of a class or function object.	Object
		usingCustomCompareFunction : Boolean [read-only] True if this ISortField uses a custom comparator function.	SortField

Public Methods

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	Method		Defined By
		SortField(name:String = null, caseInsensitive:Boolean = false, descending:Boolean = false, numeric:Object = null) Constructor.	SortField
		addEventListener(type:String, listener:Function, useCapture:Boolean = false, priority:int = 0, useWeakReference:Boolean = false):void Registers an event listener object with an EventDispatcher object so that the listener receives notification of an event.	EventDispatcher
		dispatchEvent(event:Event):Boolean Dispatches an event into the event flow.	EventDispatcher
		hasEventListener(type:String):Boolean Checks whether the EventDispatcher object has any listeners registered for a specific type of event.	EventDispatcher
		hasOwnProperty(name:String):Boolean Indicates whether an object has a specified property defined.	Object
		initializeDefaultCompareFunction(obj:Object):void A helper function called by the Sort class to set the default comparison function to perform a comparison based on one of three things: whether or not a custom compare function has been set, the data type for the specified field or the the value of the numeric property.	SortField
		isPrototypeOf(theClass:Object):Boolean Indicates whether an instance of the Object class is in the prototype chain of the object specified as the parameter.	Object
		propertyIsEnumerable(name:String):Boolean Indicates whether the specified property exists and is enumerable.	Object
		removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void Removes a listener from the EventDispatcher object.	EventDispatcher
		reverse():void Reverse the criteria for this sort field.	SortField
		setPropertyIsEnumerable(name:String, isEnum:Boolean = true):void Sets the availability of a dynamic property for loop operations.	Object
		toLocaleString():String Returns the string representation of this object, formatted according to locale-specific conventions.	Object
		toString():String Returns the string representation of the specified object.	Object
		valueOf():Object Returns the primitive value of the specified object.	Object
		willTrigger(type:String):Boolean Checks whether an event listener is registered with this EventDispatcher object or any of its ancestors for the specified event type.	EventDispatcher

Events

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	Event		Summary	Defined By
		activate	[broadcast event] Dispatched when the Flash Player or AIR application gains operating system focus and becomes active.	EventDispatcher
		deactivate	[broadcast event] Dispatched when the Flash Player or AIR application operating loses system focus and is becoming inactive.	EventDispatcher

Property Detail

arraySortOnOptions

property

arraySortOnOptions:int [read-only]

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

This helper property is used internally by the findItem() and sort() methods. Other uses of this property are not supported. Returns -1 if this ISortField shouldn't be used by the Sort class to sort the field (there is no compareFunction or no name). Otherwise, returns a bitmask of sort options..

Implementation
public function get arraySortOnOptions():int

caseInsensitive

property

caseInsensitive:Boolean

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

Specifies whether the sort for this field should be case insensitive.

The default value is false.

This property can be used as the source for data binding. When this property is modified, it dispatches the caseInsensitiveChanged event.

Implementation
public function get caseInsensitive():Boolean
public function set caseInsensitive(value:Boolean):void

compareFunction

property

compareFunction:Function

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

The function that compares two items during a sort of items for the associated collection. If you specify a compareFunction property in an ISort object, Flex ignores any compareFunction properties of the ISort's SortField objects.

The compare function must have the following signature:

function myCompare(a:Object, b:Object):int

This function must return the following values:

-1, if a should appear before b in the sorted sequence
0, if a equals b
1, if a should appear after b in the sorted sequence

The default value is an internal compare function that can perform a string, numeric, or date comparison in ascending or descending order, with case-sensitive or case-insensitive string comparisons. Specify your own function only if you need a need a custom comparison algorithm. This is normally only the case if a calculated field is used in a display.

Note if you need, language specific sorting then consider using the spark.collections.SortField class.

Implementation
public function get compareFunction():Function
public function set compareFunction(value:Function):void

Related API Elements

spark.collections.SortField

descending

property

descending:Boolean

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

Specifies whether this field should be sorted in descending order.

The default value is false (ascending).

This property can be used as the source for data binding. When this property is modified, it dispatches the descendingChanged event.

Implementation
public function get descending():Boolean
public function set descending(value:Boolean):void

name

property

name:String

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

The name of the field to be sorted.

The default value is null.

This property can be used as the source for data binding. When this property is modified, it dispatches the nameChanged event.

Implementation
public function get name():String
public function set name(value:String):void

numeric

property

numeric:Object

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

Specifies that if the field being sorted contains numeric (number/int/uint) values, or string representations of numeric values, the comparator use a numeric comparison.

This property is used by SortField class in case custom compare function is not provided.

If this property is true, the built-in numeric compare function is used. Each of data items is cast to a Number() function before the comparison.

If this property is false, the built-in string compare function is used. Each of data items is cast to a String() function before the comparison.

If this property is null, the first data item is introspected to see if it is a number or string and the sort proceeds based on that introspection.

The default value is null.

This property can be used as the source for data binding. When this property is modified, it dispatches the numericChanged event.

Implementation
public function get numeric():Object
public function set numeric(value:Object):void

usingCustomCompareFunction

property

usingCustomCompareFunction:Boolean [read-only]

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

True if this ISortField uses a custom comparator function.

Implementation
public function get usingCustomCompareFunction():Boolean

Constructor Detail

SortField

()

Constructor

public function SortField(name:String = null, caseInsensitive:Boolean = false, descending:Boolean = false, numeric:Object = null)

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

Constructor.

Parameters

	`name:String` (default = `null`) — The name of the property that this field uses for comparison. If the object is a simple type, pass `null`.

	`caseInsensitive:Boolean` (default = `false`) — When sorting strings, tells the comparator whether to ignore the case of the values.

	`descending:Boolean` (default = `false`) — Tells the comparator whether to arrange items in descending order.

	`numeric:Object` (default = `null`) — Tells the comparator whether to compare sort items as numbers, instead of alphabetically.

Method Detail

initializeDefaultCompareFunction

()

method

public function initializeDefaultCompareFunction(obj:Object):void

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

A helper function called by the Sort class to set the default comparison function to perform a comparison based on one of three things: whether or not a custom compare function has been set, the data type for the specified field or the the value of the numeric property. If the the numeric property is true, then a numeric comparison will be performed when sorting.

Parameters

obj:Object — The object that contains the data. If the field name has been set with the name property, then the name will be used to access the data value from this object. Otherwise the object itself will be used as the data value.

reverse

()

method

public function reverse():void

Language Version:

ActionScript 3.0

Product Version:

Flex 3

Runtime Versions:

Flash Player 9, AIR 1.1

Reverse the criteria for this sort field. If the field was sorted in descending order, for example, sort it in ascending order.

NOTE: An ICollectionView does not automatically update when the ISortFields are modified; call its refresh() method to update the view.

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Classes x

arraySortOnOptions

caseInsensitive

compareFunction

descending

name

numeric

usingCustomCompareFunction

SortField

initializeDefaultCompareFunction

reverse